For each Pinball game (or only one of them), which is your favourite field and why? I try to play them equally so I can catch all the Pokemon, but I still have favourites.
For the original Pinball, I'd say Blue. I think it just seems easier to me (easier to flip the ball up the side than on the Red field), and I prefer the music (especially the version of Aim to Be a Pokemon Master during Catch 'em mode). I also like how the ball gets sucked into a particular direction. Also I'm pretty bad at the Diglett bonus, though I only just started playing again.
For Ruby and Sapphire, I much prefer Ruby. I think, like Blue, it's easier, and I prefer the Kecleon bonus to the Duskclops one, although it's harder to get into the Mart on this field, I find.